With technological advances, portable terminals, such as a mobile phone, a Personal Digital Assistant (PDA), and a Portable Multimedia Player (PMP), a navigation system, and a laptop, are equipped to additionally provide short-range communication between devices, such as Digital Multimedia Broadcasting (DMB) and the wireless Internet, in addition to basic functions such as calling, playing video/music, and navigation. Accordingly, portable terminals are equipped with a plurality of antennas for wireless communication, such as wireless Internet and Bluetooth.
Further, recently, functions such as information exchange between terminals, payment, ticket booking, and searching using short-range communication (that is, NFC) have been applied to portable terminals. To this end, portable terminals are equipped with an antenna module (that is, an NFC antenna module) used for local communication. The NFC antenna module is a non-contact short-range wireless communication module, which uses Radio Frequency Identification (RFID) in a frequency band of about 13.56 Hz, and transmits data between terminals at short distances of about 10 cm. NFC is used in various areas such as the transmission of product information in supermarkets or stores, the transmission of travel information for visitors, traffic control, access control, and locking systems, in addition to payment.
Recently, markets for portable terminals such as tablet PCs and smart phones have rapidly extended. Portable terminals have a tendency to include functions, such as information exchange, payment, ticket booking, and searching, which use short-range communication (i.e. NFC). Accordingly, the demand for NFC antenna modules for use in short-range communication has increased.
In portable terminals, differential antenna type-NFC antenna modules are chiefly used. Such a differential antenna type-NFC antenna module receives signals from an external terminal through a radiator pattern and transfers signals only through a signal line connected to an end portion of the first side of the radiator pattern. Accordingly, since the strength of a signal received by a conventional NFC antenna module is weak, a problem arises in that reception performance in a reader mode is deteriorated and the recognition distance in the reader mode is shortened.